Expandible reinforcement structure for inflatable domes

ABSTRACT

An expandable reinforcement for use in connection with a building method wherein a concrete structure is erected by inflation of an underlying air impervious membrane, the reinforcing structure being arranged in the form of a regular polygon and reinforcing elements radiate from each vertex of the polygon to each other vertex, there being a distribution of the end points of said reinforcing elements at any vertex. The reinforcing elements which elongate during inflation are constructed of two rods, one hooked at one end and the other at the other end, with the unhooked ends free, and the rods slidably disposed within a coil spring. A method of vibrating the inflated structure is also disclosed.

United States Patent Bini [ Aug. 29, 1972 [54] EXPANDIBLE REINFORCEMENT STRUCTURE FOR INFLATABLE DOMES [72] Inventor: Dante Bini, Castelfranco, Emilia,

Italy [22] Filed: Nov. 20, 1969 21 Appl.No.: 878,446

[30] Foreign Application Priority Data Nov. 21, 1968 Italy ..l818 N68 [52] US. Cl. ..52/646, 52/2, 52/80 [51] Int. Cl. ..E04c 5/01, EO4b l/l8, E04g 11/04 [58] Field of Search....52/80, 81, 223, 573, 227, 646,

[56] References Cited UNITED STATES PATENTS 2,591,352 4 1952 Harbison ..52/291 3,277,219 10/1966 Turner ..52/2 X FOREIGN LPATENTS OR APPLICATIONS L. 1,027,437 4/1966 Great Britain ..52/2

Primary ExaminerPrice C. Faw, Jr. Att0rneyl-Iubbell, Cohen & Stiefel [57] ABSTRACT reinforcing elements which elongate during inflation are constructed of two rods, one hooked at one end and the other at the other end, with the unhooked ends free, and the rods slidably disposed within a coil spring. A method of vibrating the inflated structure is also disclosed.

1 Claim, 11 Drawing Figures PATENTED M2 1912 3.686131 8 SHEET 1 0F 3 J3 awe/Mon DANTE BIN! we, wwm w (Wm/nu, s

PATENIEDIUEZQ 1912 3.888 8 8 SHEET 3 BF 3 63 DANTE BIN! FIELD OF THE INVENTION This invention relates to a method of erecting concrete domelike structures by inflation of an underlying balloon or membrane and especially to improvements in reinforcements for such structures and for the method of vibrating the concrete of such structures after inflation and before setting. The closest prior art is applicants earlier U. S. Pat application Ser. No. 601,176, filed Dec. 12, 1966, granted as US. Pat. No. 3,462,521, on Aug. l9, 1969, and assigned to the assignee hereof. The contents of said patent are hereby incorporated by reference. In said earlier patent, a method of erecting a domelike structure by inflation is disclosed wherein an expandable air impermeable membrane is secured in airtight relationship with a circular foundation curb, expandable reinforcement is disposed thereover, and concrete is then poured over the reinforcement. After the concrete had been properly distributed, air under pressure is pumped under the membrane to inflate the membrane and thereby raise the building.

The expandable reinforcement in the aforementioned patent is disclosed as either similar to chain-link fencing or made of a mesh of coil springs, some of which might have a non-stretchable rod or wire therewithin to limit the expansion of the coil springs. Further development has demonstrated that the reinforcement can be improved and that is the primary subject of the present application.

The earlier patent also disclosed the use of vibration for tamping the concrete prior to setting. In the present application improved vibration techniques are disclosed.

SUMMARY OF THE INVENTION The expandable reinforcement of the present invention consists of a reinforcing frame for a domelike structure, which frame is laid out two-dimensionally and is thereafter deformed to three-dimensional shape by inflation of an underlying membrane. In two dimensional form, the frame comprises a circular element that overlies the underlying circular foundation curb to which the inflatable membrane is connected, and a multiplicity of straight reinforcing elements. The straight reinforcing elements are arranged to define a regular polygon within the circle of the circular reinforcing element, the polygon preferably having an even number of sides. Linear expandable reinforcing elements extend from each vertex of the polygon to each other vertex thereof. Preferably, any of such elements which extend through the center of the polygon terminate at the center as radial members, the end adjacent the center being hooked on to a central reinforcin g ring.

To avoid a concentration of reinforcing elements at each vertex of the polygon, the members are arranged so that they are distributed adjacent said vertices whereby to improve the distribution of reinforcement. The linear expandable reinforcing elements comprise two rods, one hooked to a suitable anchor at one end and the other hooked to a suitable anchor at the other end, with the opposite ends of each being free, the two rods lying in close parallel relationship within the interior of a spiral spring or the like.

Additionally, a novel means of tamping the concrete by vibration after erection but before setting thereof is disclosed, which means include a reel disposed at the top of the dome and a plurality of opposed vibrating means, the reel automatically paying out the length of line to cause the vibrators to move downwardly from the top of the dome, and operators having cable means connected to each of the vibrators to move them meridianally of the dome whereby to cause the vibrators to define a spiral path down the dome and thus vibrate the entire dome.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic view of a portion of a reinforcing frame for an inflatable dome shaped building;

FIG. 2 is a plan view, a part of the complete reinforcing frame;

FIGS. 2a 2b 2c and 2d are fragmentary views, partly in section and partly in elevation, relating to the anchoring of elements of the frame of FIG. 2;

FIG. 3 is a sectional view of the foundation of the building;

FIG. 4 is a view similar to FIG. 2 showing a modified frame;

FIG. 5 is a view partly in perspective and partly in section illustrating the compacting of material making up a dome shaped building by vibration;

FIG. 6 is a perspective view of an inflatable structure and illustrating part of the method of erection; and

FIG. 7 is a view similar to FIGS. 2a through 211 illustrating a linear reinforcing element.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS As already stated, the present invention is an improvement on my earlier U. S. Pat. No. 3,462,521 In that patent a novel method of erecting reinforced concrete structures of domelike shape is described. The method includes the construction of a circular foundation curb of steel or concrete, which foundation curb has a keyhole slot therein to receive the inflatable annular marginal portion of an air impervious membrane and to be sealed thereto upon inflation of the annular marginal portion. An expandable steel reinforcement is laid over the membrane and connected to the foundation curb, and concrete is then poured over the reinforcement and membrane. After the concrete has been distributed and smoothed, the membrane is inflated to thereby elevate the concrete to the configuration of the building being constructed where it is held until the concrete sets. During setting electrical vibrators may be actuated to tamp the concrete. After the concrete sets the membrane can be deflated and removed.

As stated, the present invention relates to improvements in the reinforcement used in connection with the above-described method and to improvements in the vibrating step of said method.

Referring now to FIG. 1, 1 is a circular element, preferably of iron, steel or other tough high tensile strength material, to which there is anchored the frame assembly indicated as a whole by 2, said element 1 being rigidly connected with the foundation curb, shown in dotted line, and indicated by reference numeral 3. Within the circular line defined by the element 1 there is inscribed a hypothetical polygon, for example, and in the case of FIG. 1, an octagon, form the vertices of which there extend the elements 4, shown in FIG. 1 by solid line, which join the adjacent vertices, and elements 5 located along all the possible diagonals, the vertex shown for illustrative purposes being designated by the reference numeral 6.

What has been stated with regard to the vertex 6 applies equally to all the other vertices of the octagon inscribed within the line defined by the circular element 1 including for example the vertex 7, the diagonal elements extending therefrom being shown in dashed line, and being designated by the reference numeral 8.

From what has been stated, it is clear that by proceeding in the manner described, there is produced a sort of tight net of frame elements and that the tightness is a function of the number of sides of the hypothetical polygon inscribed within the foundation curb. It is furthermore clear that if a frame is made precisely in accordance with that described, then at each vertex of the inscribed hypothetical polygon there would be a concentration of frame elements, which is not practical, since substantial areas adjacent the vertices would remain without framing as may be seen in FIGS. 2, 2a 2b 2c and 2d In order to avoid this, while maintaining the basic concept of the uniformity of frame elements, there is effected a progressive displacement of the inscribed hypothetical polygon in the foundation curb in such a manner as to avoid the concentration of the frame elements at points which are spaced relatively a great distance apart.

As a matter of fact, the frame elements, which are generally indicated in FIG. 2 by the reference numeral 11 and which are formed of coil springs, are distributed as may be seen by studying the sector indicated by reference numeral 12 -with a certain uniformity along the arc of circular anchoring element 13 (corresponding to element 1 of FIG. 1) almost as though the polygon inscribed within the element 13 were gradually rotated by a certain amount and there were a total rotation equal to the central angle intercepting one side of the polygon. In this way, there is obtained a regular distribution of the frame elements 11, which shall be referred to as main elements, and which, as stated, consist of a coil spring.

The hypothetical polygon inscribed in the circle of the element 13 preferably has an even number of sides so that there are elements 14 which pass through the center of the figure enclosed by the element 13.

The spiral elements which, as stated, constitute the main part of the frame, are anchored to the circular element 13 which is disposed above a foundation curb (not shown in FIG. 2) by means of a spring 15 placed on said element 13 in the manner of FIG. 2a so that there is an automatic uniform distribution along the element 13 of the attachments of the spiral elements 1 l.

The element 13 in its turn is connected to the foundation curb by means of U-shaped members 16 forming part of the assembly of frame elements, forming a part of the foundation curb, as will be described in detail hereinafter.

Within at least some of the spiral elements 11, there are inserted normal concrete reinforcing members of iron, steel or the like, which are indicated generally by the reference numeral 17 and which are so positioned as to intersect substantially even when the building of which the frame in question is part is erected. Of these members 17, those extending meridianally, namely, those which reach the center of the figure enclosed by the element 13 and which are indicated by reference numeral 18, have their ends bent around the peripheral element 13 and form a hook with very unequal prongs and the short prong being bent preferably in such a manner as to be disposed together with the longer prong within the spiral element 11 associated therewith.

Each meridian element 18 is formed of at least two longitudinal elements 18 a and 18b (FIG. 7) which over-lap within their associated spiral element 11 so as obviously to provide substantial continuity of reinforcement along the meridian even when the building is erected and the meridian has a considerably greater length than that which it has before the erection. The meridian element 18 also includes an end portion 19 which is hooked around peripheral element 13 (FIG. 2b and an opposite end portion 21 which is anchored to a central ring 20 as by bending (FIG. 20 Clearly, other reinforcing members in the reinforcing frame could be formed of two relatively slidable elongated members similar to members 18 a and 18b of reinforcing element 18.

To the perimetral element 13 there are also attached, since the lower zone of the building is that subjected to the greatest stress, short reinforcement members 22 which reinforce the frame in this region (FIG. 2d).

In FIG. 3 there are shown the frame elements of the foundation curb. In these frame elements there is a stirrup which has a part 33 which is bent in the manner of a fork and which holds the iron 13 and correspond to the U-shaped element 16 of FIG. 2a

The stirrup 32, including its vertical part 34, constitutes a lateral supporting element for a plug 35, further details of which will be presented hereinafter, which is adapted to yield upon the pouring of the curb, the seat for securing the membrane over which there is placed the material for forming the building or structure to be erected, e.g., concrete.

The stirrup 32 is held in position by a downwardly extending part 32a which is fastened in the concrete 36 that constitutes the bottom of the foundation trench.

The concrete 36 also holds in position a stirrup 37 which, cooperating with stirrup 32 and with a third stirrup 38 of rectangular shape held on a vertical plane by the part 32a of the stirrup 32 and by a part 39 of the stirup 37, defines a seat 40 having a restricted opening wherein the upper part of plug 35 is placed. The aforementioned plug 35 consists substantially of a pair of tubular elements 41 and 42 connected along a generatrix and forming a figure eight with the upper tube 41 thereof being of diameter significantly smaller than the diameter of the tube 42. Both tubes 41 and 42 of the plug 35 are air-tight and accordingly each of them forms, in the case of erection of buildings or structures of circular shape, a toroidal chamber. Each of these chambers communicates with the outside through flexible tubes 43 and 44 respectively which pass from the inside to the outside of the perimeter enclosed by the curb which will be produced by pouring in the foundation trench 45 through a pipe 46.

From what has been stated up to now with regard to FIG. 3, it is clear that upon pouring the concrete into the trench 45, there is created within the foundation curb an annular recess which corresponds in shape to the plug 35. Thus, there can be inserted therewithin after deflation and removal of the plug 35, marginal part of an inflatable membrane, which marginal part is constructed like the plug 35 to thereby connect the membrane to foundation curb. By over inflating the inflatable tubes forming the marginal part of the membrane, an air tight seal can be effected to permit the inflation of the space under the membrane itself to enable the practicing of the method described in my earlier U. S. Pat. No. 3,462,521. It is furthermore clear that once the structure has been so erected and has become self-supporting, it will be possible simply by opening the communications of the annular chambers forming the marginal edge of the membrane to the outside to disengage and recover the said membrane.

Referring now to FIG. 4, a modified reinforcing frame is illustrated in which non-radial reinforcing members 53 are also extendible in the manner of radial reinforcing members 18 of FIG. 2. That is the, the members 53 are formed of two or more elongated reinforcing rods which are slidably disposed within a spring with one rod hooked at one end and the other at its opposite end. During inflation members 53, in the same manner as members 18, will elongate and bend to conform to the dome shape. In FIG. 4, it will be noted that the short radially extending reinforcing members 22 of FIG. 2 are omitted (as they may also have been in FIG. 2). Likewise, members 23 are also not included in FIG. 4 (as well they may not have been in FIG. 2 also).

While the extendible members 18 and 53 include only two reinforcing rods within a coil spring 11, it will be obvious that such member could be made of more than two reinforcing members without departing from the present invention.

While the frame arrangements of FIGS. 2 and 4 are presently preferred, it will be recognized that other frame arrangmenets can be employed which include extendible reinforcing members similar to members 18 and 53 without departing from the present invention.

In my earlier US. Pat. No. 3,462,521 I have suggested the use of vibration to distribute and compact the concrete base it sets.

In FIGS. 5 and 6 there is illustrated a preferred manner of vibrating a cupola-shaped building made of concrete by my method of said aforementioned patent. As shown, the cupola-shaped building 61 is covered with an outer membrane 63, preferably of impermeable material such as Hypolon (duPont), polyvinyl chloride, or the like. Most preferably outer membrane 63 has been placed over the structure prior to erection by inflation of inner membrane 69 although it may be so positioned after inflation. Disposed on top of the dome over membrane 63 is'a spool 62. An electric conductor 65 supported by a cable 64 extends to spool 62 and is connected on the one hand to a source of electrical power and energizes the vibrating groups 66 of the type having eccentric masses and slide rollers. As seen in FIG. 6, spool 62 supports a number of vibrators 66. The spool 62 is held in position by the opposing action of the various vibrators. In addition, if desired, the spool may also be connected, directly or indirectly, to the reinforcing frame of the building. The rollers 67 of the vibrators act on the outer membrane 63 which covers the mass of concrete 68 that is supported by the inner membrane 69. Spool 62 is of the type that will slowly unwind under the weight and vibration of vibrators 66 whereby to slowly drop the vibrators from the top of the dome to the base thereof. The vibrators 66 have extending downwardly therefrom cords 71 by which, as shown in FIG. 5, it is possible to pull the vibrators in a latitudinal direction, so that they are forced, upon the unwinding of the cables from the spool 62, to move in spiral paths which cover among them and their length, the entire surface of the cupola-shaped building 61. The operation described is relatively simple and easily performed. In any event, it is clear from the foregoing that when effecting the erection of a building by the improved method in question, the production of the foundations with the corresponding seat for the inner membrane 69 adapted to raise the material producting the building or structure to be erected is a very simple operation. As a matter of fact, it is sufficient, after having dug the foundation trench, to place in position the stirrups and the reinforcing irons of the curb and at the same time the plug 35 and proceed with the pouring, being careful, however, to see to it that the toroidal chamber 41 of the said plug 35 is at least tangent to the upper plane of the curb and has a pressure greater than that to which the chamber 42 is subjected so that there will definitely be no collapse of the chamber 41 so that it is possible after the concrete: in the curb sets to remove the plug 35 and insert, within the seat which has thus been formed, the edge portion of the membrane 69.

Once the curb has been poured, there will be connected to the fork-shaped portions of the stirrup 32 which protrude from the upper surface of the said curb the circular element 13 to which there is anchored the assembly of elements of the reinforcing frame, element 13 preferably being duly threaded into the spiral element 15 as in FIG. 2a, to which there are connected the greater part of the elements constituting the frame. Thereupon the spiral elements, 11 in FIGS. 2, 2a 2b and 2c and 51 in FIG. 4, are stretched and there are inserted in them the bars which complete the frame. All of this naturally after having engaged in the seat of the foundation curb the edge portion of the membrane which lifts the material, which portion is shaped precisely like the plug 35 which, during the pouring of the foundation curb, has given rise to said seat. Once the frame has been so positioned, a layer of concrete or similar hardening material is placed over same, and the outer membrane 63 is laid over the concrete. Spool 62 and vibrators 66 may then be placed over membrane 63. There is then efiected in entirely normal manner, namely in the manner indicated, the erection of a structure by inflating air or similar fluid into the space below the membrane 69 which is anchored in the manner stated to the foundation curb. Clearly, if the outer membrane is positioned after inflation, as may be done, spool 62 and vibrators 66 will also be positioned after inflation.

Thereupon, there will be effected the vibrating of the entire unit by bringing the vibrators 66 into action in the manner described. The membrane 63 makes it possible to avoid the action of the vibrators being counteracted by the lack of a suitable resting surface and by the penetration of fluid material between the rollers. Of course, by proper arrangement, vibrators 66 could be constructed to walk latitudinally, whereby to eliminate the need for laborers to move them around. Also, it will be obvious that a plurality of vibrators can be ganged one above the other, whereby to suspend a plurality from a single cable to thus increase the speed of vibration.

What is claimed is:

1. In a reinforcing frame including a plurality of elongated reinforcing members; at least one of said reinforcing members comprising: a pair of elongated reinforcing rods in close parallel relationship; and means connected to said rods for permitting relative longitudinal movement therebetween and for preventing substantial transverse relative movement therebetween, said frame further including a plurality of angularly related radially extending members, each of said radially extending members comprising: a pair of elongated reinforcing rods in close parallel relationship; and means connected to said rods for permitting relative longitudinal movement therebetween and for preventing substantial transverse relative movement therebetween, the rods in each of said radially extending members each having one end remote from the other rod in said member and the other end adjacent said other rod in said member, and further comprising a peripheral member and a central member, and means for securing the remote ends of the rods in each of said radially extending members respectively to said peripheral member and said central member, said means for permitting longitudinal movement and for preventing transverse movement is a helical spring in surrounding relation with the two rods in each of said radially extending members, the reinforcing frame further comprising means for fixedly securing the ends of said coil springs respectively to said peripheral member and said central member. 

1. In a reinforcing frame including a plurality of elongated reinforcing members; at least one of said reinforcing members comprising: a pair of elongated reinforcing rods in close parallel relationship; and means connected to said rods for permitting relative longitudinal movement therebetween and for preventing substantial transverse relative movement therebetween, said frame further including a plurality of angularly related radially extending members, each of said radially extending members comprising: a pair of elongated reinforcing rods in close parallel relationship; and means connected to said rods for permitting relative longitudinal movement therebetween and for preventing substantial transverse relative movement therebetween, the rods in each of said radially extending members each having one end remote from the other rod in said member and the other end adjacent said other rod in said member, and further comprising a peripheral member and a central member, and means for securing the remote ends of the rods in each of said radially extending members respectively to said peripheral member and said central member, said means for permitting longitudinal movement and for preventing transverse movement is a helical spring in surrounding relation with the two rods in each of said radially extending members, the reinforcing frame further comprising means for fixedly securing the ends of said coil springs respectively to said peripheral member and said central member. 